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Date:	Wed, 4 Nov 1992 09:12:36 -0500
From:	rsalz@osf.org
Message-Id: <9211041412.AA11509@earth.osf.org>
To:	malte@techfak.uni-bielefeld.de, rc@hawkwind.utcs.toronto.edu
Subject: Re: set subtract

>A related builtin I always wanted to have:
>        idx = `{ index list_of_patterns list_to_search_in }
>This should return a list of indices of the search patterns in the second list.
>        ; echo `{ index a ( a b c a ) }
>        1 4
Easy; the following just uses built-ins.  Note that it implements
the example (first arg is a pattern, not a list of patterns); I don't
believe the synopsis can be done.
fn index { pat=() i=() result=() count=() {
    pat=$1
    shift || { echo 'Usage error' >[1=2] ; return 1 }
    for (i) {
        count=(a $count)
        eval ~ $i $pat && result=($result $#count)
    }
    echo $result
} }